Magnetic switch



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INVE/VTUR WILLIAM I? GARDINER United States Patent 01 as 3,529,269 MAGNETIC SWITCH William P. Gardiner, 4822 36th St., Columbus, Nebr. 68601 Filed Aug. 1, 1966, Ser. No. 569,375 Int. Cl. H0111 9/22 US. Cl. 335-207 12 Claims ABSTRACT OF THE DISCLOSURE In the prior, art attempts have been made to construct a successful switch of this type, and of particular interest is the German patent to Zuckschwerdt, issued in December of 1962, Pat. No. 1,141,000. My experiments have shown that when a switch is constructed as in Zuckschwerdt with the inner magnet rigidly attached to the moving contact, then when the moving contact strikes the stationary contacts, the amount of bouncing is so great as to cause a very serious impairment in the effectiveness and life of the switch with each bounce of the switch. When the moving contact bounces, it is caused by magnetism to again strike the moving contacts and to bounce again. These motions are repeated causing many bouncings each of a lesser distance from the stationary contacts.

With each of these bouncings, there is both an opening and closing of the switch with accompanying arcing. Such a switch has a much shorter life. And its inability to closeand remain substantially closed makes it impractical.

It is my belief that it is for this reason that switches of this type have not been successfully produced in the great commercial quantities that one would expect in view of the explosion-proof, dust-proof, and moistureproof possibilities that such a sealed switch could give the world.

The U8. Pat. No. 3,273,091, issued Sept. 13, 1966, to N. B. Wales, Jr. is titled, Hermetically-Sealed Manually- Actuated Magnetic Snap Switch. This Wales patent also shows the absence of means for preventing bouncing, as its moving magnet does not have a spring attached to it. Although FIG. 7 of the Wales patent shows leaf springs supporting contacts, these springs are not mounted on a reciprocating magnet and they are not stated in the Wales patent to be for the purpose of preventing bouncing.

The US. Pat. No. 3,025,372, issued Mar. 13, 1962 to Louis Benson, and titled, Reciprocating Type Actuating Means, shows in its FIG. 1 a reciprocating magnet to which moving contacts are attached by means of resilient material such as foam rubber. The use of resilient material is stated in the Benson patent, column 2, lines 495l, as being optional expedients to be utilized if relatively noiseless operation is desired. It is evident from Bensons patent that this foam rubber was intended to be only for reducing noise and is not of a composition designed or intended for reducing bounce with its attendant arcing as in my invention.

Further in the Benson patent and in column 2, lines 5759, it is stated: The contact bridging plate may also take the form of a resilient member itself, in the form of a metallic spring, though not shown as such.

3,529,269 Patented Sept. 15, 1970 Presumably here again Benson had no appreciation of the problem of bouncing and intended to use a spring or resilient member in substitution for the foam rubber for the mere purpose of relative noiseless operation.

Additionally, the Benson mention of a metallic spring is stated in a form indicating that the metallic spring is used in substitution for the movable contact which he calls the contact bridging plate. This means that Benson did not have in mind placing a spring between a contact bridging plate itself and the magnet, as is a separate difference from the question of using a resilient spring to prevent bouncing.

An object of the invention is to provide a switch which can be manufactured in a practical form more economically than the switch described in my earlier co-pending patent application, Ser. No. 507,966, filed Nov. 15, 1965, entitled, Switch With Magnetically Controlled Inner Rotating and Reciprocating Elements, which is now Pat. No. 3,402,376, issued Sept. 17, 1968.

Still another object is to provide such a switch with the housing so structurally arranged that its threaded portion is on the same end as its leads and on the opposite end from its push-button whereby the switch can be mounted on a panel by emplacement into the panel from the forward side of the panel, so as to speed and simplify installation in equipment with crowded panels.

Still another object is to provide, in a switch as described, the feature of a spring between the moving contact and the inner magnet for minimizing bouncing upon contact closure.

Yet another object is to provide, in a switch as described, an arrangement of parts providing the switch with a more compact structure.

Still another object is to provide a relay in which a coil disposed on the outside of the enclosure can influence movement of an inner magnetically attracted element in each of two directions as current is reversed in the coil, with the inner element closing a switch.

A further object is to provide a relay as described in which the energizing of the coil moves the inner element in one direction and the de-energizing of the coil permits the inner element to be returned in an opposite direction by a spring.

A further object is to provide a thermostatically controlled switch in which a heating coil around a bimetallic element causes the bimetallic element to bend when the coil is energized, the bimetallic element actuating the plunger on the switch.

A further object is to provide a switch in which the contact leads are mounted in a cuplike member for gaining a perfection of alignment, and a still further object is to provide the switch with a wall lining element facilitating proper emplacement of the cuplike member, the wall lining element further insulating the contact area from a conductive housing.

SUMMARY OF THE INVENTION An electrical switch of a type having a reciprocating inner magnet carrying a moving contact in which the contact is connected to the inner magnet by means of a spring having a resiliency selected for the purpose of reducing bouncing of the moving contact and the attendant arcing, the switch having an externally threaded housing portion on the same end as its leads to facilitate mounting from one side of a panel. The externally threaded housing portion forms a part of an enclosure having therein the contacts. An inner magnet receiving enclosure housing portion opens upon and forms an integral part of the externally threaded housing portion for leak-proof construction and for economy by eliminating the step of assembly that would be necessary if these two housing portions were separate whereby it would be necessary to attach them together.

FIG. 1 shows a circuit breaker employing the switch of this invention.

FIG. 2 is a vertical section taken through the switch of FIG. 1.

FIG. 3 is a sectional view taken along the line 33 of FIG. 2.

FIG. 4 shows a modification of the right-hand portion of the switch of FIG. 2 in which the push-button and its retainer housing are replaced by a coil.

FIG. 5 is a modification of the left-hand side of FIG. 2 with right-hand side portions broken away.

FIG. 6 is a modification of a right-hand side of the switch of FIG. 2 with the left-hand side broken away, with a coil replacing the push-button and a push-button retainer housing, the modification utilizing a spring.

Referring to FIG. 1, an electrically controlled thermally operated switch assembly is there shown and generally indicated at 10 having a switch generally indicated at 12. The switch 12 has a plunger 14 at one end and has a pair of leads protruding from its other end and has an enclosure or threaded bearing housing 24 having a threaded area 26 disposed inwardly of the leads 20.

A bimetallic element 30 is mounted in a position so that one of its ends 32 is free to move in each of two directions as indicated by a double arrow 36 in accordance with thermal conditions around the element 30, the opposite end of the element 30 being attached to a suitable mounting 38.

An electrical coil is disposed around the bimetallic element 30 between the switch 12 and mounting 38 so that heat from the coil 40 will cause the bimetallic element 30 to bend. One end of the coil 40 is shown at 44 connected to one of the leads 20'.

The other lead 20 is connected by a wire 48 to one terminal 50 of a source of power. The other terminal 52 of the same source of power is connected by a wire 56 to a terminal 60 of an imaginary element to be controlled, the other terminal 62 of that element being connected by a wire 64 to the opposite side of the coil 40.

In operation, the switch is normally closed whereby energy is reaching the imaginary element at the terminals 60 and 62. The flow of energy will continue until sufiicient heat is built up in the coil 40 to cause the bimetallic element 30 to move toward the opposite end of the switch depressing the plunger, as causes the switch to open as later described. The opening of the switch then breaks the flow of energy allowing the coil 40 to cool. This permits the bimetallic element 30 to move in an opposite direction permitting the plunger to move out from the switch as causes the switch to close once again.

The imaginary element 61 connected to the terminals 60 and 62 can be a motor, for example, and when the current through the coil 40 is sufficiently strong, the coil 40 will heat, causing the plunger 14 to be depressed and the switch to open.

As thus described, the thermally operated switch assembly 10 functions as a most effective circuit breaker.

Referring to FIG. 2, the switch 12 will be seen to have an inner element of magnetically attracted material, preferably a permanent magnet. The magnet 70 is surrounded by a frame 72 on which the inner element 70 is mounted in a manner for moving in each of two opposite directions 78 and '80, toward and away from two stationary swtich contact means or switch contacts 84 and 86, which latter are disposed adjacent but spaced from each other. i

A moving contact 80 is disposed between the inner element 70 and the stationary contacts 84 and 86. The inner magnetic element 70 is connected to the moving contact by a spring assembly 98 which is adapted to reduce bouncing when the moving contact 90 strikes the stationary contacts '84 and 86 because of the resiliency of the spring 98 which tends to compress permitting th inner magnetic element 70 to move independently of the moving contact 90 in a direction toward the stationary contacts 84 after the moving contact 90 has engaged the contacts 84 and 86.

The switch further has an external element 100 spaced from the inner element 70 and having a magnetic interattraction with the inner element, as can be accomplished by having the external element 100 in the form of a permanent magnet of annular shape having a central opening 104 of cylindrical shape closely but slidably fitting the cylindrical exterior wall of an inner magnet receiving housing portion 112 which latter has an end wall closing the end of the housing portion 112 which is 0pposite the moving contact 90.

The interior of the housing portion 112 is preferably also provided with a cylindrical wall 124 and the inner magnet 70 preferably has a cylindrical exterior.

All parts described as cylindrical have a common axis 126 extending through the center of the switch.

An enclosure 130 which can also be called a housing 130 is formed of a moving contact housing portion 24 having an exterior provided with threads 26, the housing portion 24 being cylindrical on its inner and outer sides and symmetrical about the axis 126.

The enclosure housing 130 further has a connecting portion 134 of annular shape and which interconnects the housing portion 112 with the housing portion 24 in a manner which is airtight and watertight, the entire housing 130 further having a lead-carrying end closure portion 138 which closes the outer end of the housing portion 24 and by forming a part of the total enclosure 130 tends to create a completely enclosed interior having a floating contact chamber 140 and a inner magnet chamber 144, the chambers 14!) and 144 being interconnected. The leads 20 are embedded in the lead-carrying housing portion 138 and are attached to the stationary contacts 84 and 86 respectively, whereby the latter the exposed on the inner side of the enclosure 130 where they are engageable by the moving contact 90. The outer ends of the leads 20 extend outwardly of the leadcarrying housing member 138.

The outer magnet 100 is fixed to and mounted in the plunger 14, being received in a recess on the inner side thereof and the plunger 14 has a spring-receiving recess 152 of a lesser diameter than the recess 150, the recess 152 extending into the plunger 14 from its inner side and being for the purpose of receiving a coiled compression spring 156 which latter engages an end wall 158 of the spring-receiving recess 152 and also engages the end wall 120 of the inner magnet housing 112 so that the plunger 14 is constantly urged in an outer direction and in the direction of the arrow 80.

The plunger 14 is limited in its movement in the direction of the arrow 80 by the engagement of a shoulder on the plunger 14 with a shoulder 174 which extends inwardly from the end of a plunger retaining housing generally indicated at 176 which is opposite the contact 90, the shoulder 174 extending toward the axis 126 beyond the outer side of the shoulder 170 which latter has a larger diameter and size than the remainder of the plunger 14 so that the plunger 14 is effectively retained by the plunger retaining housing 176 from moving excessively in the direction of the arrow 80.

The housing portion 176 is suitably fixed by a tight fit or other means at 180 to the housing or envelope 130 at a flange portion thereof or external shoulder providing means 184 which extends annularly outwardly from the housing portion 24 in the direction normal to the axis 126.

The plunger 14 is free to move a sufficient distance between the shoulder 174 and the housing portion 184 for moving the magnet 100 in the direction of the arrows 78 and 80 sufficiently to cause the inner magnet 70 to move back and forth in the direction of the arrows 78 and 80. The inner magnet 70 thus moves sufficiently for causing the moving contact 90 to press against and to separate from the stationary contacts 84 and 86.

As best seen in FIG. 3, the stationary contacts 84 and 86 are preferably provided with surfaces 192 and 194 which face the moving contact 90, which latter surfaces are preferably of approximately semi-cylindrical shape for providing arcuate edges 200 which are spaced from but which are coaxial with the cylindrical interior 202 of the stationary contact chamber 140, the curve surfaces 200 being sections of a circle arranged about the axis 126.

The stationary contacts 84 and 86 are each not completely semi-circular, however, as they are spaced apart, each being spaced from the axis 126. It is desirable that the contacts 84 present a maximum area of surface for engagement by the moving contact 90 consistent with an adequate spacing apart of the contact surface connected to the one lead from the contact surface connected to the other lead 20.

Referring to FIG. 4, a modification of the switch is there shown in which the plunger 14 is not used and its retainer housing 176 is not used and even the outer magnet 100 is not used, being replaced by an electrical coil 240 which closely surrounds the housing 112 coaxially with the axis 126 of the switch, whereby when a current is passed through the ends' 246 and 248 of the coil 240 in one direction, the inner magnet 70 is caused to move toward the contacts 84 and 86 and when the current through the coil 240 is reversed, the inner magnet 70 is caused to move away from the contacts 84 and 86.

Referring now to FIG. 6, a similar modification is shown in which similar parts will be given similar numbers, but in which a coiled compression spring 250 for inner magnet return is disposed between the inner magnet 70 and the housing wall 120 for causing the inner magnet 70 to be urged toward the contacts, while in operation the current energizing the coil 240* tends to influence the inner magnet 70 causing it to move away from the stationary contacts.

Referring to FIG. 5, there will be seen a modification of the left-hand portion of the switch in which the leadcarrying member is given the numeral 338 to indicate that it is a modification of the lead-carrying member 138, in which the member 338 is formed in two main portions, a first portion being a cuplike lead carrying member 340 having a cylindrical outer portion 342 snugly received in and sealed to the inner wall 344 of the threaded housing portion 424, which latter is a number chosen to signify that it is a modification of the housing portion 24 of the switch of FIG. 2.

The inner wall 344 is cylindrical and is centered about the axis 126, and it will be seen that the outer cylindrical portion 342 of the lead carrying member 340 extends a partial distance inwardly from the outer end 425 of the housing portion 424 toward the housing portion 130.

The remaining space along the inner wall 344 and between the lead carrying member 340 and the housing portion 134 is occupied by a liner 430 which has a cylindrical outer portion 432 of a sufficient size such that during assembly, the positioning of the liner 432 in the housing portion 424 before the insertion of the lead carrying member 340, will cause the lead carrying member 340 to be ideally positioned for the proper positioning of the stationary contacts.

The liner 432 is of electrical insulating material and its tight engagement against the cuplike member 340 tends to prevent arcing from reaching the housing portion 424 which can, therefore, be safely made of electrically con ductive material.

The housing portion 424 and the housing portion 134 and also the housing portion 112 and end wall 120 are all preferably integrally made of aluminum, whereby they are integrally formed of this material which is not magnetically attracted whereby it will not disturb the action of the magnet.

Lug-carrying member 338 has its cup-shaped portion or member 340 provided with openings 440 therethrough through which the leads 20 extend. The inside of the cup-shaped member 340 is filled with a material 444 which is adapted to seal the leads 20 to the cup-shaped member 340 holding them firmly in place with respect thereto and completing the enclosure of the moving contact chamber 140.

As best seen in FIG. 2, the south poles of the magnets 70 and 100 both face the contacts 84, 86, and 90, whereas the opposite side of each of the magnets is the north pole. This has been found to have the effect of reducing the arcing because the south pole has a beneficial elfect upon the contact area.

Referring to FIG. 2, it will be seen in operation that whenever the plunger is outward, as shown, the south pole of the outer magnet 100 will be repulsing the south pole of the inner magnet and the north pole of the outer magnet will simultaneously repulse the north pole of the inner magnet causing the inner magnet to be forced in the direction of the arrow 78 for pressing the moving contact against the stationary contacts 84 and 86.

The repulsion described is sufficient to overcome the amount of attraction there is between the south pole of the outer magnet and the north pole of the inner magnet.

When the plunger is pushed inwardly in the direction of the arrow 78, the outer magnet will move until it engages the housing portion 184 at which time the south pole of the outer magnet is farther to the left than the south pole of the inner magnet whereupon repulsion begins to drive the inner magnet to the right in the direction of the arrow 80 opening the switch and the inner magnet 70 continues to move to the right until it engages the end wall remaining in this position as long as the button 14 is sufliciently pressed inwardly. When the operator lets go of button 14, the spring 156 will cause it to move to the right until it has reached the position shown in FIG. 2 whereupon it once again drives the inner magnet to the left for again closing the switch.

The contacts described can be defined also as a first contact means comprising a pair of separate contact means 84 and 86, insulated from each other, and a second or bridging contact means 90.

The flange portion 184, as earlier stated, can also be called an external shoulder providing means 184 attached to one of the housings and disposed a substantial distance from each end of both of the housings on the exterior of the switch for engaging a panel, not shown, on the opposite side of the panel from the threads in the threaded area 26.

The inner magnet receiving housing portion 112 can be called a second portion of the sealed housing and the first portion of the sealed housing is formed of the sealed housing portion which receives the contacts and which is formed of the parts of the sealed housing which are between the flange 184 and including the lead end of the sealed housing formed by the lead-carrying closure portion 138. The second portion of the sealed housing is of susbtantially lesser size than the size of the first portion of the sealed housing as seen linearly of the line of reciprocation of the inner magnet 70, and the outer magnet 100 extends inwardly toward the path of reciprocation of the inner magnet 70 beyond the inner side of the first portion of the sealed housing for helping to provide a compact arrangement.

I claim:

1. A panel mountable magnetic switch comprising: a sealed housing, an inner magnet disposed inside said housing, a first contact means comprising a pair of separate contact means in said sealed housing, means in said sealed housing insulating said pair of contact means from each other, a second contact means comprising a bridging contact means in said housing, said inner magnet reciprocating in each of two opposite directions toward and away from one of said first and second contact means, means mounting the other of said first and second contact means on said inner magnet and between said inner magnet and said one of said contact means, said housing surrounding said inner magnet and said contact means, and an external magnet means disposed outside of said sealed housing and reciprocating in said two directions for magnetically causing said reciprocating movements of said inner magnet, a pair of leads having outer ends disposed outside of said housing at one of the ends of said housing, means electrically attaching said pair of leads one to each of said pair of contact means, said external magnet means being actuable for reciprocation toward and away from said one of said first and second contact means along a line of reciprocation, an outer housing disposed outside of said sealed housing and attached to sald sealed housing and disposed on a plurality of those sides of the area of reciprocation of said outer magnet which sides are disposed laterally of said line of reciprocation, said switch having a threaded substantially cylindrical surface on the exterior of one of said housings, movable external magnet actuating means disposed on the other end of said sealed housing from the lead end thereof and connected to said external magnet for mechanically controlling said reciprocating movements of said'external magnet, said actuating means being disposed partly in said outer housing and partly projecting through that end of said outer housing which is opposite said leads, and shoulder-providing means providing an external shoulder attached to one of said housings and disposed a substantial distance from each end of both of said housings and disposed on the exterior of said switch, said external shoulder extending laterally of said line of reciprocation to at least one side of said housing beyond said threaded exterior, said external shoulder facing at least part of said threads, whereby said switch can be mounted on a panel with one end of said threads on one side of the panel, its actuating means on the outside of said panel and its leads on the inner side of the panel and with its external shoulder means engaging that side of the panel which is opposite said end of said threads.

2. The combination of claim 1 in which said sealed housing has a first portion containing said contacts and a second portion containing said inner magnet, said second portion of said sealed housing being of substantially lesser size than the size of said first portion as seen linearly of said line of reciprocation, and said outer magnet means extending inwardly toward the path of reciprocation of said inner magnet beyond the inner side of said first portion of said sealed housing for helping to provide a compact arrangement.

3. The combination of claim 1 further including actuating means mounting means of which said outer housing forms a part, said actuating means mounting means further comprising means attached to said outer housing and operably correlated with said outer magnet actuating means to movably mount said actuating means on said sealed housing.

4. The combination of claim 1 in which said outer housing is attached to said sealed housing partially by a flange attached to said sealed housing and extending from said sealed housing laterally of said line of reciprocation, said flange defining said shoulder providing means.

5. The combination of claim 4 in which said threads are on said inner housing.

6. The combination of claim 1 in which said threads are on the inner one of said housings.

7. The combination of claim 1 in which said mounting means comprises a compression spring.

8. The combination of claim 1 in which actuating means is a plunger having an exposed surface disposed opposite the lead end of said sealed housing, said plunger reciprocating in each of said two directions, a spring engageable with said plunger for urging said plunger in a direction away from said one contact means, and means comprising said outer housing for attaching said plunger to said sealed housing in a manner for the said reciprocattion of said plunger.

9. The combination of claim 8 in which said plunger has a recess on that side thereof which faces said moving contact, said spring being disposed in said recess.

10. The combination of claim 8 in which said plunger has a recess on that side thereof which faces said moving contact, said spring being disposed in said recess, said plunger being slidably received on the adjacent end of said sealed housing for reciprocating with respect thereto.

11. The combination of claim 1 in which said leads are mounted in'a lead-carrying member, said lead-carrying member forming an end wall of said sealed housing on said one end thereof, said lead-carrying member being attached to but not integral with the remainder of said sealed housing.

12. The combination of claim 11 in which said leadcarrying member is cuplike on that side thereof which faces away from said contacts.

References Cited UNITED STATES PATENTS 2,531,025 11/1950 Bradley 335-l93 XR 3,025,372 3/1962 Benson 335207 3,196,231 7/1965 Meyer 335193 3,264,424 -8/ 1966 Baermann 335207 3,361,999 1/1968 Leinauer et al. 335-205 XR FOREIGN PATENTS 1,141,000 12/ 1962 Germany.

BERNARD A. GILHEANY, Primary Examiner D. M. MORGAN, Assistant Examiner US. Cl. X.R. 1 200--67 

